In recent years the use of large hay bales has become more common. These hay bales are so large and bulky that they must be lifted and transported only by mechanical means, and for this purpose apparatus has been devised to assist the farmer in lifting and transporting large bales of hay. Reference may be had to copending Application Ser. No. 927,837, filed July 25, 1978, now U.S. Pat. No. 4,194,863, entitled "BIG BALE LOADER" for an example of a type of loading apparatus for lifting and transporting hay bales. The type apparatus disclosed in the pending application is particularly adapted for mounting on the front of a vehicle, such as a tractor.
The present invention is directed towards a type of loader for big hay bales which is particularly adapted for mounting on the rear of tractors having a three-point hookup. Most small and intermediate size farm tractors in use in the United States today have what is termed a three-point hookup. This consists of an upper stationary pivot point and a pair of hydraulically controlled lifting arms which are positioned below the pivot point. The lifting arms are pivoted about a common axis and are hydraulically controlled so that the arms are raised simultaneously up and down utilizing hydraulic energy supplied by a pump driven by the tractor engine. Control mechanisms are mounted on the tractor. This typical type of three-point hydraulically controlled hookup is popular because it allows the tractor operator to attach a great variety of agricultural implements to the tractor and affords means of controlling the implements. It is particularly useful with implements such as plows, mowers, discs, and so forth which can be lifted off the ground for transportation to and from work areas.
It is therefore an object of this invention to provide an improved loader for large hay bales particularly adaptable for the attachment to the rear end of a tractor.
More particularly, an object of this invention is to provide a big bale loader for the rear end of tractor having a three-point hookup wherein the hydraulic system for lifting large bales of hay primarily utilizes controls already existing on tractors having three-point hookups and wherein the only auxiliary hydraulic control required is the provision of a grasping cylinder-piston for engaging or disengaging the lifting apparatus with large bales of hay.
These general objects as well as other and more specific objects of the invention will be fulfilled in the following description and claims taken in conjunction with the attached drawings.